Bearing



taining aluminium v been used in-the production of bearings, which Patented Dec. 22, 942

BEARING Adolf Beck and Walter Buchmann,

by meme ano s,

Magneaium Development Corporation, a corporation of Delaware No Dra No. 291,322. In

wing. Application August 22, 1939, Serial German August 22, 1938 4 Claims. (Cl. 308-242) This invention relates to bearings.

Certain commercial magnesium base alloys conand zinc have occasionally however have given good results only when subjected to small loads, that is to say, in a limited field of application. Thus for example, the attempt to mount camshafts in crank-cases made of these alloys has been successful. This is due to the fact that even pure magnesium itself has relatively good sliding properties, probably due to its hexagonal crystal'structure. The known commercial magnesium alloys, however, are unsuitable for bearings which are pressures and, in particular, speeds. They lack, in particular, the essential property of being able to form, through running-in, a'bearing surface which is uniformly loaded; in the event of the shaft being tilted, and particularly if lubrication should fail temporarily, local increases in temperature therefore readily occur on the bearing surfaces, rapid destruction of the bearing. The so-called bearings made It has now been ascertained, in accordance with the present invention, that the properties necessary to the more extensive use of magnesium base alloys as hearing metal, are obtained by the use of alloys of magnesium with the metals lead and/or cadmium, both of which form solid solutions with magnesium up to relatively high con--- presence of which not only-does rather increases, the plastic propthe bearing properties of the resultant alloys deteriorate.

The bearing metal alloys of the present invention preferably contain to of lead and/or 7 to 12% of cadmium. Silver, bismuth and tin also may advantageously be present in the foregoing alloys in amounts of up to 12%, but only provided that the total content of alloy formers in the alloys does not exceed about By comparison withhitherto proposed light bearing metal alloys, the bearing metal alloys of the present invention possess more favourable enhanced.

running-in properties, due to their which lead to the present invention provides abearfurther up to about 12% of 50 alloy plastic properties. They are quite generally suitable for bearing purposes for light to medium loads and, in this range of use, are equivalent in respect to their sliding properties to known heavy metal bearing alloys, over which latter they have the important advantage of lower specific gravity;

For heavier loadsfsuch as those occurring in internal combustion engines, the alloys of the present invention are somewhat deficient in re-' spect of fatigue strength and heat strength.

However, these properties can be substantially improved without unduly impairing the plastic properties and the-ability to form good running surfaces, by additionally incorporating with the alloys, cerium in amounts of from about 0.5 to 10%. The amount of the cerium addition depends not only on the intended use, but also on the amount of other alloy formers contained in i the alloy. Thelincrease in strength atelevated temperatures becomes appreciable, for example in the case of alloys having a high lead content, only when the added amount of cerium is high.

The following are examples of bearing metal alloys in accordance-with the invention:

I. 18% of lead, remainder magnesium.

II. 12% of lead, 8% of cadmium, remainder magnesium. i; g

III. 7% of lead, 7%'of cerium, remainder mag- IV.- 10% ofcadmium, 5 magn sium.

We claim:

l. A bearing made from a magnesium base alloy. containing between about 15 and about 20% of lead, the balance be 31m 2.. A hearing from a magnesium base alloy containing between about 1 and about 28% of lead, at least one metal of the group, consisting of silver, bismuth and tin, and between about 0.5 and about 10% of cerium, the total content of the alloying constituents stated not exceeding about 35%, and the balance of cerium, remainder being substantially magnesium.

.3. A bearing made from a magnesium base alloy containing about 18% of lead, the balance being substantially magnesium.

4. A bearing made from a magnesium base said alloy containing between about 1 and about 28 per cent lead, the balance being substantially magnesium.

ADOLF BECK.

WALTER. BUCHMANN.

g substantially magne- 

